Is it reasonable to be a global warming skeptic?


Michael Mann is very close to “losing it all”.

Michael Mann has spent so much time boxing himself into a corner that he has no place left to go.


But that is just the point. You don’t need to assess his credibility. You don’t need to treat him as an expert witness. What he says you can independently verify or contradict. If you can contradict it, do so. It not as if what he is saying is so technical that a layperson cannot understand it. It is not as if the facts he mentions are so hidden that you cannot look them up for yourself. If you find anything Mann said in that video that you can prove is wrong, then just do so. I don’t care what you think of Mann as a person. What I think of him does not matter either. All that matters for this discussion is the content of what he said in that video I posted, because this discussion was not about Mann. It started out as an analysis of “Hide the Decline.” I introduced the Mann video only because he had a succinct way of explaining the facts associated with that term. I still have no idea which parts of the content of that explanation you are challenging.


Mann addresses the “hide the decline” this way: There is a divergence problem. Temps as measured by tree rings diverge from the surface temp record starting around 1960. (We conjecture as to the cause, but we can’t really explain it.) Therefore the post 1960 data is “bad” and shouldn’t be used. Therefore Jones was justified in deleting the data. It would be misleading not to delete it. After all, we wouldn’t want to confuse the unsophisticated readers of the WMO report. And even if it were important to anyone to know about the deletion, whether layman or scientist, everyone was put on notice about the divergence problem by an article in Nature.

This is garbage.

  1. The data is “bad.” See my response at post 284. The only problem with the data is that it stops correlating with the surface temp record and thus is not suitable for the purpose of their nice tidy story.
  2. Jones was justified in deleting the decline because we don’t want to confuse the lay audience. This is laughable. Can’t these guys get their story straight? Jones tried to justify the trick to hide the decline because WMO report was directed at sophisticated scientists. My point is: No matter the audience, if you are going to use the Briffa series in a spaghetti graph, use all of it. Your nice tidy story be damned. Your job as a scientist is not to mask uncertainties with tricks. Both of us agree that the divergence problem creates doubts about the use of tree ring proxies as a measure of temperature. Why does this fact have to be hidden from anyone?
  3. Jones was not deceitful in deleting the decline because the world was put on notice of its existence in the Nature article. This is laughable too. There is no Central Notice System in science that exempts one from full disclosure.
  4. Note also that Mann justifies Jones’ deletion, but makes no mention of Jones’ splicing, a practice he criticizes in his book. Deleting is wrong for the reasons given, but the splicing is the smoking gun of fraud. You can’t take a tree ring curve and then seamlessly join it to a surface temperature curve, as if they constitute one data set. But then Mann isn’t trying to fully educate the public. He is trying to pull the wool over their eyes and further the narrative.

The video is just further proof that Mann is a Disgrace to the Profession.


Yes, we can explain it. We just haven’t proved it.

Take the scare quotes away and your overlay of assuming motives, and your description is accurate. The data is bad. Surface temperatures are more reliable than modern tree ring data, otherwise weather stations at airports would be composed of a stand of trees that are sampled every day.

The trick needs very little justification. It is a good trick.

If the purpose of the graph was to prove the accuracy of various proxies, then I would agree. Then it would be dishonest to suppress bad data. But that was not the subject of the graph.

That depends on whether those uncertainties are important to the subject being discussed.

It is not hidden when the subject being discussed is the reliability of proxies.

Full disclosure only applies to relevant information. For the graph in question, it was not relevant.

Did the graph say it was composed exclusively of tree ring data? If so, I agree. That was misleading. The graph should only say “temperature anomaly”. Then it would not be a fraud.

Actually, we merge and splice and blend temperature data all the time. The many many surface temperature stations each produce a single data set. Some of them go back in time further than others. Some of them have interruptions. Some of them were moved. But they are spliced and blended with the “trick” of averaging.


There is no justification for faking the data.

You certainly cannot take unscientific data and call it scientific.


And you can’t take true data and call it faked.


I think there are some effects with mankind but I don’t agree with the Church joining the enemy those that push population control and abortion.



Thanks to the emails we know what their motive was, namely to show that the late 20th century warming was unprecedented in 1000 years. Briffa called this the “nice tidy story” which he, at least for a brief moment, resisted.

The image of dendrochronologists taking tree ring samples at airports made me chuckle, but it causes me ask this question: Why start using instrumental data in 1980 (1960 in the case of the Briffa series) and not earlier, given that the instrumental data is more reliable? The reason is they were trying to tell the story with proxies. They wanted the reader to see how remarkably the three different data sets, all using proxies, were in agreement. They wanted to demonstrate the overall reliability of proxies so that the reader will believe their temperature reconstructions for periods back in time before the instrumental record begins. The caption of the WMO graph does mention instrumental records are in the mix, but gives us no details.

So while we don’t measure tree rings at airports to get the current temps, we do gather such data for periods for which we have instrumental data so that we can calibrate and verify our reconstruction models. For this purpose it would be helpful to have proxy series as current as possible so we can have more data to work with. But then why do most proxy series stop at 1980? Why haven’t the paleo guys and gals updated them? Mann says its because its too costly. McIntyre debunked that when he took a trip to Colorado to visit his sister. He had coffee at Starbucks in the morning, sampled some tree rings during the day, and got back to his sister’s place in time for supper. I suspect updating the proxies would risk generating more “bad” data.



You didn’t respond to my post at 298. Are you a member of the CSELBTIPCC?


You mean thanks to the cherry-picked and spoon-fed emails taken out of context you are led to believe what the cherry-pickers wanted you to believe.

Thank you. I’m glad I brought some joy to your day.

They could have switched over to instrumental data at some earlier point and the graph would not have been substantially different. When there is a large period of overlap in which the two series are in agreement, you can switch over at any time. It is only when they are not in agreement that you must be more careful about which series you use. Yes, they were trying to present the temperature record that relied on proxies for the older readings. But the graph was not part of a presentation on the reliability of proxies. So I disagree that the graph was made for the purpose of proving the reliability of proxies. If it were that, then I would agree that any suppression of non-conforming data would have been unethical. But it was not that.

We don’t need to gather more bad tree ring data. We already have enough bad tree ring data to confirm that any more modern tree ring data we take is likely to be bad as well. Gathering more data will do nothing to improve the calibration of ancient reconstructions. We already have enough overlap with good data to do that. And as far as I know, research on ancient reconstructions is still going on.

The problem with the modern version of proxies is that they are affected by modern changes. Modern aerosols can affect what bands of the sunlight spectrum reach the leaves and that can affect tree ring density. Modern tree ring samples have not been dead long enough to be comparable to long-dead trees. I would not be surprised to see that if the same trees that we find to be non-conforming are sampled again 100 years from now and are found to be conforming then. There are so many possible ways in which modern trees could be affected by factors that did not affect ancient trees that it would be quite surprising if they the did have tree rings that track temperature in exactly the same way as ancient trees.


The historical context of the hide the decline emails was explained earlier. They were working on the zero order draft. Folland fretted that Briffa’s data set “diluted the message” of an unprecedented warming in the last 1000 years. Briffa resisted the push for a “nice tidy story” and argued that things weren’t that certain. Briffa capitulates and they delete the decline in the Working Group I report. Meanwhile Jones is also working on his WMO graph. He writes his infamous hide the decline email. That’s the context. What emails were ignored by the “cherry-pickers” that would lead us to conclude these guys weren’t struggling with how to handle the divergence problem and trying to hide the uncertainties?


Charges that something has been cherry-picked usually mean no more than this:

You have cited something that completely refutes my position, and to which I have no reasonable objection. Therefore I will charge you with malfeasance and ignore your comment.”


All he has to do is come out and say things didn’t go as he planned and he’ll be more scientific.

It’s always okay to take a second look. I wouldn’t point and laugh at him “told you so” if he did.


He and his fellow alarmists would end up giving up a lot of grants.


It is also useful to follow Mark Steyn:

He has taken Mann to court.

For example:


I have Steyn’s book. Why Mann still feels free to show his face in public is an indictment of so many. Penn State, the entire paleo community, every scientific academy which didn’t denounce him, the IPCC,… He is walking, talking proof of the corruption of the entire climate industrial complex.

The guy even had the chutzpa to claim in his court pleadings that he was a Nobel prize winner. He had to amend his complaint. Just because the IPCC was awarded the prize for its work on climate change and you were one of thousands who participated in its work doesn’t mean you are a Nobel winner.


An interesting chart from this article
What crisis? Global CO2 emissions stalled for the third year in a row


It is just another sign of climate change. :grin:


I believe there are effects of some of the things we have done on this planet but I think some people take it a tad too far.



Science is SUPPOSED to be debated and discussed; it is never settled.

On top of which, Al Gore has no … zero … none … scientific credentials of any kind.

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